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Ophthalmology

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Cornea

Question
35 out of 52
 

Transparency of the cornea is maintained by all except: (AIIMS Nov 2011)



A Mitotic figures in the central cornea

B Wide separated collagen bands

C Hydration of the corneal epithelium

D Unmyelinated nerve fibers

Ans. C Hydration of comeal epithelium

Corneal transparency is due to:

1. Relative dehydration of cornea, which itself is maintained by

a. Anatomic integrity of the endothelium & epithelium

b. Endothelial pump removes fluid from the stroma

c. Evaporation of water from the tear increases osmolarity of tear, which draws water from cornea

d. Normal intra-ocular pressure ( if too high,relative hydration occurs)

2. Relative acellularity, lack of blood vessels and pigments

3. Regular matrix structure of corneal fibrils

a. The corneal stroma doesn't scatter light because its collagen fibrils are small in diameter (300 Angstrom.) and closely packed

b. Destructive interference of light occurs

4. Consistent refractive index of all layers.

Cornea Flashcard List

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